Below you can see the front view size comparison of Sony HX100V and Nikon P510. Nikon P510 is 2mm narrower and 4mm shorter than Sony HX100V but it is also 9mm thicker.
Sony HX100V vs Nikon P510 - Front View
Sony HX100V vs Nikon P510 - Top View
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.
Camera Size Comparison
Select Two Cameras for Size Comparison